// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

// Fast asynchronous logger.
// Uses pre allocated queue.
// Creates a single back thread to pop messages from the queue and log them.
//
// Upon each log write the logger:
//    1. Checks if its log level is enough to log the message
//    2. Push a new copy of the message to a queue (or block the caller until
//    space is available in the queue)
// Upon destruction, logs all remaining messages in the queue before
// destructing..

#include "abel/log/logger.h"

namespace abel {

// Async overflow policy - block by default.
    enum class async_overflow_policy {
        block,         // Block until message can be enqueued
        overrun_oldest // Discard oldest message in the queue if full when trying to
        // add new item.
    };

    namespace details {
        class thread_pool;
    }

    class ABEL_API async_logger final : public std::enable_shared_from_this<async_logger>, public logger {
        friend class details::thread_pool;

    public:
        template<typename It>
        async_logger(std::string logger_name, It begin, It end, std::weak_ptr<details::thread_pool> tp,
                     async_overflow_policy overflow_policy = async_overflow_policy::block)
                : logger(std::move(logger_name), begin, end), thread_pool_(std::move(tp)),
                  overflow_policy_(overflow_policy) {}

        async_logger(std::string logger_name, sinks_init_list sinks_list, std::weak_ptr<details::thread_pool> tp,
                     async_overflow_policy overflow_policy = async_overflow_policy::block);

        async_logger(std::string logger_name, sink_ptr single_sink, std::weak_ptr<details::thread_pool> tp,
                     async_overflow_policy overflow_policy = async_overflow_policy::block);

        std::shared_ptr<logger> clone(std::string new_name) override;

    protected:
        void sink_it_impl(const details::log_msg &msg) override;

        void flush_impl() override;

        void backend_sink_it_(const details::log_msg &incoming_log_msg);

        void backend_flush_();

    private:
        std::weak_ptr<details::thread_pool> thread_pool_;
        async_overflow_policy overflow_policy_;
    };
}  // namespace abel

#include "abel/log/async_logger_inl.h"
